In the paper converting industry, rewinding machines are used for the production of tissue paper articles in the form of wound rolls, such as bath tissue, paper toweling, and the like. These rewinding machines generally have the function of rewinding a web material coming from large reels (so-called parent reels) into logs having a diameter equal to the diameter of the wound finished articles which are then sold to consumers. These logs are much longer than the axial length of the finished articles that are sold. Therefore, the logs are generally cut square to their axis to obtain the finished product which is subsequently packaged.
Winding or rewinding a web material is usually performed in a continuous manner at high speed. For example, winding one single log can occur in about 1-3 seconds. At the end of winding a log, the web material is severed (i.e. torn or cut) to create a trailing edge of web material for the finished log and a leading edge of web material for a succeeding (e.g., next) log. Severing the web material, discharging the finished log, and the beginning of winding of the next log are generally known to those of skill in the art as an exchange phase or operation. This operation is performed typically without interrupting or slowing down the feed of the web material in order to maintain a set hourly throughput.
Winding a web material usually occurs around tubular winding cores. The leading edge of the web material is typically adhered to the core material with an adhesive. Some operations may utilize suction provided from inside an apertured core material. In still other embodiments, a tubular core can be electrostatically charged to attract the free leading edge of the web material.
Surface rewinding machines provide for the winding of a log that is in contact with the surface of at least two winding rollers. More precisely, the log is formed starting from a continuous web material that is provided with transverse perforations. The perforated web material is carried by a first conveyor and is wrapped at least partially around an upper winding roller. A core having adhesive disposed thereon is placed into contacting engagement with the web material disposed about the upper winding roller. The material-adhered core then enters into contact with a lower winding roller and is kept in rotating engagement between both the upper and lower winding rollers with a pressure roller. The three rollers form a ‘cradle’ and define a ‘winding zone’ wherein the wound log is formed by rotating the core and disposing the web material onto the core as it rotates within the winding zone.
The core can be inserted into the winding zone in a plurality of manners. In a first case, one a core at a time can be fed onto a loading tray and a pusher disposes the core into the winding zone. Here, the pusher forces the core into position between the winding rollers. This can result in the core being dented in the winding zone and producing a faulty winding.
In a second method, the core can be brought on a feeding cradle of curved shape located under the upper winding roller. Friction against the upper roller brings it forward up to the contact with the lower winding roller for starting the winding. The cradle is formed by a series of integral curved guides that protrude rearwardly from the lower winding roller. According to the size of the core, the lower roller is brought forward or away from the upper roller. However, a different cradle is necessary for each different diameter of the core. This causes stops in the production, an adjusting work and the need of a set of cradles, one for each different diameter of the core.
A third method provides an inserter that allows for independent movement of pneumatically activated fingers disposed across the width of the rewinder that grip an incoming core and translate it to the winding zone. An exemplary inserter that functions in this manner is shown in FIGS. 1 and 2. As can be seen, this method positively controls the motion of the finger in only one direction and has significant variability in speed due to contaminants in the process and the fragility of the design. This can lead to failure to insert the core at the right time in the wind cycle, release of the core prematurely, or even impeding the core from insertion by the insertion finger causing jams, web breaks, and roll wraps.
Thus, it would be easily recognized by one of skill in the art that a better system for inserting cores into the winding cradle of a surface rewinding system is needed. Such an improved winding system would provide better control of the core during the insertion process, provide a more reliable and consistent insertion in production, and provide an insertion system that is not as effected by contamination generated during the rewinding process.